Altaeros Energies, a Massachusetts-based business, is developing an airborne wind turbine. The device uses a turbine blade made of lightweight composite aluminum surrounded by a circular shroud of laminate material that both focuses the wind and keeps the turbine aloft.

Altaeros is preparing to launch a one-third scale prototype which is expected to generate 100 kilowatts.

Since the whole device will fit into a shipping container, the company hopes that it will be used for humanitarian operations following natural disasters, as well as for powering remote military bases, drilling camps or small villages which are off the grid and now rely on expensive diesel generators.

Several other companies are developing aerial wind turbines which can take advantage of the much stronger winds at higher altitudes – winds at 1,000 metres can be eight times stronger than at the 100 metre height of a typical wind turbine. Makani Power in California and researchers at the University of Delft in the Netherlands each have designed kite-like airfoils that circle the sky to generate electricity through their tethers, while another Californian company, Joby Energy, is building a flying rectangular array of turbines that it hopes will generate two megawatts of power.